Leaky Plate Wave Inspection of Biaxial Composites

Abstract

The utilization of leaky plate waves in a scanning arrangement has exhibited improved reliability and increased sensitivity to important defects in unidirectional material [1,2,3].The application of frequency modulation to the usual tone burst signal used to generate plate waves has also been shown to enhance defect discrimination [2,3].In the current work, leaky plate wave techniques have been applied to the inspection of biaxially laminated graphite-epoxy composites.Test samples having 8, 16, and 24 plies, respectively, are studied.Test specimens contain several types of defects — simulated delaminations, porosity, and ply cuts.In addition, a series of impact-damaged samples are examined to study the method’s sensitivity to this type of delamination.All simulated defects were detected, and comparisons with conventional normal-incidence C-scan measurements have shown that the plate wave technique is more sensitive to both porosity and ply cuts, consistent with our observations on uniaxial composites [3]. Novel gating methods have been applied to the plate wave spectra to improve defect detection in biaxial composites.KeywordsMedian FrequencyPlate WaveSimulated DefectDefect DepthSpectral ProcessingThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.